Various forms of solid state solar energy conversion systems are known and used in the art with varying degrees of economy, efficiency and ease of manufactures, there being tradeoffs between each of these desirable goals. One form of energy conversion uses the thermodielectric effect to convert solar radiation to electrical energy, as is disclosed in Hoh U.S. Pat. Nos. 3,073,974 and 3,243,687, incorporated herein by reference. The materials disclosed in the Hoh patents are in the class of ferroelectric energy converters which are very temperature dependent in the neighborhood of the ferroelectric Curie point. The metal-insulator-semiconductor (MIS) art is now well developed and infrared imaging systems using inversion mode operated MIS devices with charge coupled devices (CCD), wherein an inversion region or layer is created at the insulator-semiconductor interface into which photogenerated minority are collected are known, see the article by Andrew J. Steckl et al entitled "Application of Charge Coupled Devices to Infrared Detection and Imaging", published in the IEE publication "Charge Coupled Devices: Technology and Applications" copyrighted in 1977, and incorporated herein by reference.
The objects of the present invention include providing improved radiation and solar energy conversion systems and devices. In achieving these objects, the present invention, in one preferred mode, utilizes a very thin ferroelectric material as the insulator of a MIS device. In another aspect of the invention, a very thin, low heat capacity ferroelectric material having thermodielectric properties is utilized as the insulator in a MIS device. In still another and preferred aspect of the invention solar energy is converted first into thermal and subsequently into electrical energy utilizing a thin ferroelectric layer having pyroelectric properties, the thin ferroelectric layer constituting the insulator in a MIS device, the voltage produced by the pyroelectric conversion in the ferroelectric layer operates to create an inversion region or layer in the semiconductor body and a virtual PN junction. In such state, the utilization of the charge storage and transfer ability of an electroded polarized insulator (e.g. a ferroelectric body member having dipole structure) and semiconductor interface affords the separation of electron whole pairs and the taping of corresponding electrical energy.
The thermally released electrical energy generated by the polarisable dielectric appears on the surface of the dielectric and is used only for causing the necessary bias for producing the inversion layer, which process essentially does not consume much more energy than needed to charge the virtual junction and most of which charge is regained at the end of the cycle.